I refinanced with Joshua Barthel last year to drop my rate with pretty close to no cost (took a couple months of payments to break even on the difference). He was able to offer the best rate and lowest fee of any bank or broker at the time (though two other brokers were able to match those rates/fees).
Josh was always quick to reply by email (usually less than 24 hours, little longer on the weekends but can't complain about that). He's busy at times when rates drop, but still picks up the phone or calls back the same day.
Like nearly all Zillow offers, his quote did not initially include the Title fees which are around $500 (again, like most if not all other quotes on Zillow). This was a surprise, but I understand it's common - not a mark against him, though it is against Zillow's quote system.
The best/main part of the service was the cost and low rate. Nothing fell through the cracks and I wasn't concerned about dishonesty or other issues I've faced when dealing with other brokers (from Zillow and elsewhere). I'd have preferred if my local broker could have offered a similar rate, but they just couldn't come close so I was happy to use Josh at NorthPointe and he's as good as you could want in an on-line broker refi.
They kept the loan (so far) and their automatic payment and website registration is basic but easy.